Module aws_lambda_powertools.utilities.parameters.appconfig

AWS App Config configuration retrieval and caching utility

Functions

def get_app_config(name: str, environment: str, application: Optional[str] = None, transform: Literal['json', 'binary', 'auto', None] = None, force_fetch: bool = False, max_age: Optional[int] = None, **sdk_options) ‑> Union[str, list, dict, bytes]

Retrieve a configuration value from AWS App Config.

Parameters

name : str
Name of the configuration
environment : str
Environment of the configuration
application : str
Application of the configuration
transform : str, optional
Transforms the content from a JSON object ('json') or base64 binary string ('binary')
force_fetch : bool, optional
Force update even before a cached item has expired, defaults to False
max_age : int, optional
Maximum age of the cached value
sdk_options : dict, optional
SDK options to propagate to start_configuration_session API call

Raises

GetParameterError
When the parameter provider fails to retrieve a parameter value for a given name.
TransformParameterError
When the parameter provider fails to transform a parameter value.

Example

Retrieves the latest version of configuration value from App Config

>>> from aws_lambda_powertools.utilities.parameters import get_app_config
>>>
>>> value = get_app_config("my_config", environment="my_env", application="my_env")
>>>
>>> print(value)
My configuration value

Retrieves a configuration value and decodes it using a JSON decoder

>>> from aws_lambda_powertools.utilities.parameters import get_app_config
>>>
>>> value = get_app_config("my_config", environment="my_env", application="my_env", transform='json')
>>>
>>> print(value)
My configuration's JSON value

Classes

class AppConfigProvider (environment: str, application: Optional[str] = None, config: Optional[botocore.config.Config] = None, boto3_session: Optional[boto3.session.Session] = None, boto3_client: Optional[ForwardRef('AppConfigDataClient')] = None)

AWS App Config Provider

Parameters

environment : str
Environment of the configuration to pass during client initialization
application : str, optional
Application of the configuration to pass during client initialization
config : botocore.config.Config, optional
Botocore configuration to pass during client initialization
boto3_session : boto3.session.Session, optional
Boto3 session to create a boto3_client from
boto3_client : AppConfigDataClient, optional
Boto3 AppConfigData Client to use, boto3_session will be ignored if both are provided

Example

Retrieves the latest configuration value from App Config

>>> from aws_lambda_powertools.utilities import parameters
>>>
>>> appconf_provider = parameters.AppConfigProvider(environment="my_env", application="my_app")
>>>
>>> value : bytes = appconf_provider.get("my_conf")
>>>
>>> print(value)
My configuration value

Retrieves a configuration value from App Config in another AWS region

>>> from botocore.config import Config
>>> from aws_lambda_powertools.utilities import parameters
>>>
>>> config = Config(region_name="us-west-1")
>>> appconf_provider = parameters.AppConfigProvider(environment="my_env", application="my_app", config=config)
>>>
>>> value : bytes = appconf_provider.get("my_conf")
>>>
>>> print(value)
My configuration value

Initialize the App Config client

Expand source code 
class AppConfigProvider(BaseProvider):
    """
    AWS App Config Provider

    Parameters
    ----------
    environment: str
        Environment of the configuration to pass during client initialization
    application: str, optional
        Application of the configuration to pass during client initialization
    config: botocore.config.Config, optional
        Botocore configuration to pass during client initialization
    boto3_session : boto3.session.Session, optional
            Boto3 session to create a boto3_client from
    boto3_client: AppConfigDataClient, optional
            Boto3 AppConfigData Client to use, boto3_session will be ignored if both are provided

    Example
    -------
    **Retrieves the latest configuration value from App Config**

        >>> from aws_lambda_powertools.utilities import parameters
        >>>
        >>> appconf_provider = parameters.AppConfigProvider(environment="my_env", application="my_app")
        >>>
        >>> value : bytes = appconf_provider.get("my_conf")
        >>>
        >>> print(value)
        My configuration value

    **Retrieves a configuration value from App Config in another AWS region**

        >>> from botocore.config import Config
        >>> from aws_lambda_powertools.utilities import parameters
        >>>
        >>> config = Config(region_name="us-west-1")
        >>> appconf_provider = parameters.AppConfigProvider(environment="my_env", application="my_app", config=config)
        >>>
        >>> value : bytes = appconf_provider.get("my_conf")
        >>>
        >>> print(value)
        My configuration value

    """

    client: Any = None

    def __init__(
        self,
        environment: str,
        application: Optional[str] = None,
        config: Optional[Config] = None,
        boto3_session: Optional[boto3.session.Session] = None,
        boto3_client: Optional["AppConfigDataClient"] = None,
    ):
        """
        Initialize the App Config client
        """

        super().__init__()

        self.client: "AppConfigDataClient" = self._build_boto3_client(
            service_name="appconfigdata",
            client=boto3_client,
            session=boto3_session,
            config=config,
        )

        self.application = resolve_env_var_choice(
            choice=application,
            env=os.getenv(constants.SERVICE_NAME_ENV, "service_undefined"),
        )
        self.environment = environment
        self.current_version = ""

        self._next_token: Dict[str, str] = {}  # nosec - token for get_latest_configuration executions
        # Dict to store the recently retrieved value for a specific configuration.
        self.last_returned_value: Dict[str, str] = {}

    def _get(self, name: str, **sdk_options) -> str:
        """
        Retrieve a parameter value from AWS App config.

        Parameters
        ----------
        name: str
            Name of the configuration
        sdk_options: dict, optional
            SDK options to propagate to `start_configuration_session` API call
        """
        if name not in self._next_token:
            sdk_options["ConfigurationProfileIdentifier"] = name
            sdk_options["ApplicationIdentifier"] = self.application
            sdk_options["EnvironmentIdentifier"] = self.environment
            response_configuration = self.client.start_configuration_session(**sdk_options)
            self._next_token[name] = response_configuration["InitialConfigurationToken"]

        # The new AppConfig APIs require two API calls to return the configuration
        # First we start the session and after that we retrieve the configuration
        # We need to store the token to use in the next execution
        response = self.client.get_latest_configuration(ConfigurationToken=self._next_token[name])
        return_value = response["Configuration"].read()
        self._next_token[name] = response["NextPollConfigurationToken"]

        # The return of get_latest_configuration can be null because this value is supposed to be cached
        # on the customer side.
        # We created a dictionary that stores the most recently retrieved value for a specific configuration.
        # See https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/appconfigdata/client/get_latest_configuration.html
        if return_value:
            self.last_returned_value[name] = return_value

        return self.last_returned_value[name]

    def _get_multiple(self, path: str, **sdk_options) -> Dict[str, str]:
        """
        Retrieving multiple parameter values is not supported with AWS App Config Provider
        """
        raise NotImplementedError()

Ancestors

Class variables

var client : Any

Inherited members